A cellular communications network typically comprises a plurality of individual cells. A cell is typically controlled by a base station, which may be connected to a backbone network by a wire-line connection. The backbone network may connect base stations to each other, to base station controllers or to core network nodes. Base stations communicate with mobile stations within cell coverage areas of their cells using a wireless radio interface. A base station may control more than one cell.
When a mobile terminal moves around in a coverage area of a cellular network, it may change attachment from one cell to another, a process known as a handover. Should the mobile terminal require services of the network, such as internet access or mobile telephony, it may be configured to contact the cell it is attached to. Should the mobile terminal on the other hand be an endpoint of an incoming communication, the network may be furnished with a database indicating which cell the mobile terminal is attached to, so that the incoming communication can be routed from the network side to the correct cell. The database may be updated each time the mobile terminal changes attachment from one cell to another.
In some networks, instead of recording in the database which cell each mobile terminal is attached to, the network may be sectioned into areas each comprising a plurality of cells. In these networks, the database may store for each mobile terminal an identity of such an area, such that the area comprises the cell the mobile terminal is attached to. Such areas may generally be referred to as location areas, wherein specific technologies may employ alternative terminology such as routing area or tracking area.
When a mobile terminal is an endpoint of an incoming communication, such as for example a phone call, the network may be configured to refer to the database to determine, which location area comprises the cell the mobile terminal is attached to. The network may then signal to each cell comprised in the location area, that there is an incoming communication to the mobile terminal.